LXD VM Nested Virtualization

LXD
#1

I have a LXD VM for Windows 11 that is up and running just fine. I have enabled virtualization on my Ubuntu 22.04 LXD Intel host with:

sudo modprobe kvm_intel nested=1

I have verified that virtualization is enabled:

cat /sys/module/kvm_intel/parameters/nested

On my Windows 11 LXD VM I have installed wsl from an administrator powershell prompt:

wsl --install

This appears to complete without error. Unfortunately, when I reboot the Win11 LXD VM, I get a blue screen prompting me to do a repair and I can’t seem to get past it.

Any ideas? This VM is for dev testing. I do not run any bare metal windows in my lab and I wanted wsl2 for testing.

1 Like
#2

I’ve also run into this on occasion but then I’ve also had it work on some other platforms.
Sadly Windows isn’t exactly providing a ton of logs on what’s going on…

I’ve been running nested VMs on Linux though and that’s worked fine, so it suggests that the LXD/QEMU setup should be functional…

#3

So, LXD VMs should allow nesting if I have QEMU Nested support enabled on the host?

#4

Yep, we do CPU flag passthrough by default (which is the main thing you need) and we don’t filter any of those flags (which is how other virtualization solution prevent nested virt).

#5

After much testing, I was able to do nested virtualization on a QEMU Windows 11 guest. My test was installing WSL2 inside of the guest. The Windows 11 LXD-VM on the same host corrupted upon the reboot after installing WSL2. So, something is different and I am not sure what it is.

#6

I am also experiencing the same phenomenon.

In addition to this case in my case, I have also tried “windows 11 on libvirt” and confirmed that it crashes as well and displays a blue screen!

I am assuming that if the guest OS is windows, the VM nesting settings are not being reflected correctly, but what would do you think?

#7

@y-hashida I have addressed the Windows 11 LXD question in two of my videos “Windows 11 LXD Virtual Machine” and “More Windows 11 LXD Virtual Machine” on my YouTube channel https://youtube.com/@scottibyte.